Tags added via list view on dot walked tag column are not added to the record on referenced table.
Steps to Reproduce
1. Go to incident.list on any base instance (london or madrid)
2. Configure ==> List Layout to show the Assigned To.Tags
3. Identify the incident record where Assigned To is not empty
3. On the list view add the tags to the column "Assigned To.Tags"
4. Note that no tags are added to record on sys_user table (aasigned to is referenced from sys_user)
5. Instead the tag is added on the incident record.
After carefully considering the severity and frequency of the issue, as well as the cost and risk of attempting a fix, a decision has been made not to address this issue in any current or future releases. We do not make this decision lightly and we apologize for any inconvenience.
As a workaround, open the object through the form view, and insert the tags on that object directly through the form, not through any list view or list report.
Related Problem: PRB1339684